You could have somesort of retaining tracks made up to hold filter in place, or just go get a piece of 1/8 in metal rod and cut it a so it reaches from the back to the front of blower compartment.You can make one and put it down the center under blower or two and put one on each side.I have even used a piece of 2 x 4 going across filter.And no it doesnt get hot or else the filter made of cardboard would be a problem.Cut metal rod slightly longer so they will wedge them selfs in.